Oligomer Removing Agent for Polyester-Based Fiber Material

ABSTRACT

An oligomer removing agent for polyester-based fiber materials comprises a polyester copolymer which is obtained by polycondensation of a dibasic acid component containing 15-65 mol % of a sulfonate group-containing dibasic acid and a dihydric alcohol component containing polyethylene glycol with a molecular weight of 900-3500, and which has a 200° C. melt viscosity of 5000-23,000 mPa·s and has 10-40 mass % polyoxyethylene chains in the molecule. The oligomer removing agent is able to overcome the problems caused by deposition of polyester oligomers, when added to the dyeing bath in a dyeing step for polyester fiber materials or for fiber materials that are composites thereof with other fiber materials.

TECHNICAL FIELD

The present invention relates to an oligomer removing agent that issuitable for polyester-based fiber materials that are polyester fibermaterials and composite materials of polyester fiber materials withother fiber materials.

BACKGROUND ART

Polyester-based fiber materials that are polyester fiber materials andcomposites thereof with other fiber materials are usually dyed underhigh temperature conditions of 100-140° C., but polyester oligomerscause various troubles by eluting from the polyester-based fibermaterial onto the fiber surfaces or into the dyeing bath. The seriousproblems that are faced are shadow spots or calender contamination thatoccur when the polyester-based fiber material is a fabric, and powdergeneration or winding yarn breakage that occur when it is a yarn. Inorder to solve such problems, methods have been adopted that involveadding oligomer removing agents to the dyeing bath or to thereduction/cleaning bath after dyeing. For example, Japanese UnexaminedPatent Publication No. 2000-154466 discloses a method for preventingtrouble resulting from oligomer deposition, by adding to the dyeing bathan oligomer removing agent comprising a sulfonic acid salt ofpolyoxyethylenestyryl phenyl ether, and a carboxyl group-containingpolymer such as an acrylic acid or methacrylic acid polymer or a saltthereof. Also, Japanese Unexamined Patent Publication No. 2001-295136discloses a method for preventing oligomer elution wherein during thedyeing step there is added to the dyeing bath an oligomer preventingagent comprising an ester of a polyhydric alcohol-alkylene oxideaddition product and an alkyl or alkenyl fatty acid, or an esterobtained by transesterification between a polyhydric alcohol-alkyleneoxide addition product and a natural animal or vegetable fat or oilcontaining an alkyl or alkenyl fatty acid. However, the polyesteroligomer removing effect is low even with addition of such oligomerremoving agents or preventing agents, and it is not possible at thecurrent time to achieve a satisfactory oligomer removing effect,especially with acidic baths.

DISCLOSURE OF THE INVENTION

It is an object of the present invention to provide an oligomer removingagent for polyester-based fiber materials which can solve the variousproblems caused by deposition of polyester oligomers, by its addition tothe dyeing bath in the dyeing step for a fiber material composed of apolyester fiber material or a composite material thereof with anotherfiber material.

As a result of much diligent research with the aim of solving theaforementioned problems, the present inventors have discovered that theproblem of oligomer deposition in the dyeing step for polyester-basedfiber materials can be overcome by using as the oligomer removing agenta polyester copolymer obtained by polycondensation between a dibasicacid component comprising a sulfonate group-containing dibasic acid in aspecified amount and a dihydric alcohol component containingpolyethylene glycol in a specified amount, and have completed thisinvention on the basis of this discovered knowledge.

Specifically, the invention provides an oligomer removing agent forpolyester-based fiber materials, characterized by comprising a polyestercopolymer which is obtained by polycondensation of a dibasic acidcomponent containing 15-65 mol % of a sulfonate group-containing dibasicacid and a dihydric alcohol component containing polyethylene glycolwith a molecular weight of 900-3500, and which has a 200° C. meltviscosity of 5000-23,000 mPa·s and has 10-40 mass % polyoxyethylenechain in the molecule.

Because the oligomer removing agent of the invention is polyestercopolymer-based, it has high affinity with polyester oligomers andallows oligomers to be stably maintained in water. Moreover, since theoligomer removing agent of the invention contains a sulfonate group, theoligomers do not become redeposited on the fiber material or dyeingmachine, and therefore the agent can be suitably used in dyeing steps.

BEST MODE FOR CARRYING OUT THE INVENTION

Preferred modes of the invention will now be explained with theunderstanding that the invention is not limited only to these modes, andthat various modifications may be made as are within the spirit andscope of the invention.

The oligomer removing agent of the invention comprises a polyestercopolymer obtained by polycondensation of a dibasic acid componentcontaining 15-65 mol % of a sulfonate group-containing dibasic acid anda dihydric alcohol component containing polyethylene glycol with amolecular weight of 900-3500. As preferred sulfonate group-containingdibasic acids there may be mentioned metal salts of sulfoterephthalicacid, 5-sulfoisophthalic acid and 4-sulfophthalic acid, as well as theirester derivatives such as dimethyl esters, diethyl esters and diphenylesters. As metal salts there may be mentioned lithium salts, sodiumsalts, potassium salts and magnesium salts, among which sodium andpotassium salts are particularly preferred. The content of the sulfonategroup-containing dibasic acid in the dibasic acid component is in therange of 15-65 mol %. The polyester oligomer removing power will beimpaired if the sulfonate group-containing dibasic acid is present atless than 15 mol % in the dibasic acid component. This is believed to bebecause a low sulfonate group content lowers the oligomerdispersibility, leading to redeposition of the oligomer in the fibermaterial. On the other hand, a content exceeding 65 mol % will impedepolycondensation reaction of the polyester copolymer. As dibasic acidsother than sulfonate group-containing dibasic acids in the dibasic acidcomponent used for copolymerization there may be mentioned aromaticcarboxylic acids such as terephthalic acid, isophthalic acid,naphthalenedicarboxylic acid, diphenyldicarboxylic acid,diphenoxyethanedicarboxylic acid, β-hydroxyethoxybenzoic acid andp-hydroxybenzoic acid and aliphatic carboxylic acids such as adipicacid, sebacic acid, maleic acid and succinic acid, and there may also beused their acid anhydrides or ester derivatives thereof with loweralcohols or glycols.

The oligomer removing agent of the invention further containspolyethylene glycol with a molecular weight of 900-3500, as a dihydricalcohol component, in a different starting material for synthesis of thepolyester copolymer to be used in the agent. A molecular weight of lessthan 900 for the polyethylene glycol will tend to lower the oligomerremoving power, while a molecular weight of greater than 3500 will tendto impair the dispersibility of the disperse dye. The polyestercopolymer also contains 10-40 mass % of polyoxyethylene chains derivingfrom the polyethylene glycol. A polyoxyethylene chain content of lessthan 10 mass % will tend to reduce the removing power of the oligomer,while a polyoxyethylene chain content of greater than 40 mass % willtend to increase the frequency of problems such as insufficient dispersedye dispersibility and high foamability during the dyeing process.Ethylene glycol is preferred as a dihydric alcohol other than thepolyethylene glycol in the dihydric alcohol component used for synthesisof the polyester copolymer, but there may also be used aliphatic oraromatic diol compounds including C3 or greater alkylene glycols,neopentyl glycol, bisphenol A, bisphenol S and the like.

The polyester copolymer used for the oligomer removing agent of theinvention preferably has a 200° C. melt viscosity of 5000-23,000 mPa·s.According to the invention, the 200° C. melt viscosity may be measuredusing a CV-1S cone-plate viscometer by M.S.T. Engineering, selecting acone type and rotation rate suitable for the melt viscosity, based onthe manufacturer's instruction manual. According to the invention, amelt viscosity of less than 5000 mPa·s will tend to reduce the polyesteroligomer removing power, and may lower the affinity of the oligomerremoving agent with the polyester-based fiber material. A melt viscosityof greater than 23,000 mPa·s will increase residue of the oligomerremoving agent on the polyester-based fiber material, possibly adverselyaffecting the subsequent finishing step. The oligomer removing agent ofthe invention, that comprises a polyester copolymer satisfying theconditions including the sulfonate group-containing dibasic acidcontent, the content of polyoxyethylene chain from polyethylene glycolwith a molecular weight of 900-3500 and the 200° C. melt viscosity, ischaracterized by exhibiting an excellent ability to remove oligomersfrom polyester-based fiber materials and minimizing their redepositiononto polyester-based fiber materials and dyeing machines. From thestandpoint of handleability, the oligomer removing agent of theinvention is preferably used as an aqueous dispersion or emulsioncontaining the polyester copolymer at 10-50 mass %.

The process for producing the polyester copolymer of the invention maybe any conventional process such as transesterification or directpolymerization, without any particularly restrictions.

As polyester-based fiber materials from which oligomers are to beremoved using the oligomer removing agent of the invention, there may bementioned polyester fiber materials composed of polyethyleneterephthalate, polybutylene terephthalate, polypropylene terephthalate,polytrimethylene terephthalate and their copolymers, or composite fibermaterials composed of these polyester fiber materials in combinationwith other synthetic or natural fiber materials, while the form of thefiber material may be a yarn, knitted fabric, woven fabric, nonwovenfabric or the like.

The dyeing process used for dyeing of the polyester fiber material orcomposite fiber material using the oligomer removing agent of theinvention may be an immersion process which may include jet dyeing,cheese dyeing, beam dyeing, Obermaier dyeing, high-pressure injectiondyeing or the like, but any process may be employed without anyparticular restrictions so long as it allows the object of the inventionto be achieved.

The invention will now be explained in greater detail using examples,with the understanding that the invention is in no way limited in scopeby the examples.

EXAMPLE 1

In a reactor there were charged 116.4 g (0.6 mol) of dimethylterephthalate, 118.4 g (0.4 mol) of dimethyl 5-sulfoisophthalate sodiumsalt, 57 g of ethylene glycol, 86 g of polyethylene glycol with amolecular weight of 1000 and 0.1 g of zinc acetate, and the temperaturewas increased from 150° C. to 230° C. over a period of 3 hours withstirring under a nitrogen gas atmosphere for transesterification, whiledistilling out the methanol from the system. Next, 0.1 g of tetrabutyltitanate was added, the pressure was gradually reduced to an internalpressure of approximately 10 kPa, and reaction was conducted at 250° C.for 2 hours to obtain 314 g of a polyester copolymer. The content ofpolyoxyethylene chains in the obtained polyester copolymer wasapproximately 27 mass %, and the 200° C. melt viscosity as measuredusing a CV-1S cone-plate viscometer by M.S.T. Engineering was 12,000mPa·s, after selecting the type of cone and rotation rate suitable forthe melt viscosity as according to the manufacturer's instructionmanual.

EXAMPLE 2

The same procedure was carried out as in Example 1, except for charginginto the reactor 155.2 g (0.8 mol) of dimethyl terephthalate, 59.2 g(0.2 mol) of dimethyl 5-sulfoisophthalate sodium salt, 58 g of ethyleneglycol, 131 g of polyethylene glycol with a molecular weight of 2000 and0.1 g of zinc acetate, to obtain 340 g of a polyester copolymer. Thepolyoxyethylene chain content of the obtained polyester copolymer wasapproximately 38 mass %, and the 200° C. melt viscosity was 20,000mPa·s.

EXAMPLE 3

The same procedure was carried out as in Example 1, except for charginginto the reactor 135.8 g (0.7 mol) of dimethyl terephthalate, 88.8 g(0.3 mol) of dimethyl 5-sulfoisophthalate sodium salt, 54 g of ethyleneglycol, 136 g of polyethylene glycol with a molecular weight of 1000 and0.1 g of zinc acetate, to obtain 350 g of a polyester copolymer. Thepolyoxyethylene chain content of the obtained polyester copolymer wasapproximately 38 mass %, and the 200° C. melt viscosity was 8100 mPa·s.

EXAMPLE 4

The same procedure was carried out as in Example 1, except for charginginto the reactor 97 g (0.5 mol) of dimethyl terephthalate, 148 g (0.5mol) of dimethyl 5-sulfoisophthalate sodium salt, 61 g of ethyleneglycol, 38 g of polyethylene glycol with a molecular weight of 2000 and0.1 g of zinc acetate, to obtain 280 g of a polyester copolymer. Thepolyoxyethylene chain content of the obtained polyester copolymer wasapproximately 13 mass %, and the 200° C. melt viscosity was 8900 mPa·s.

EXAMPLE 5

The same procedure was carried out as in Example 1, except for charginginto the reactor 77.6 g (0.4 mol) of dimethyl terephthalate, 177.6 g(0.6 mol) of dimethyl 5-sulfoisophthalate sodium salt, 60, g of ethyleneglycol, 39 g of polyethylene glycol with a molecular weight of 1000 and0.1 g of zinc acetate, to obtain 290 g of a polyester copolymer. Thepolyoxyethylene chain content of the obtained polyester copolymer wasapproximately 13 mass %, and the 200° C. melt viscosity was 7500 mPa·s.

EXAMPLE 6

The same procedure was carried out as in Example 1, except for charginginto the reactor 116.4 g (0.6 mol) of dimethyl terephthalate, 118.4 g(0.4 mol) of dimethyl 5-sulfoisophthalate sodium salt, 61 g of ethyleneglycol, 83 g of polyethylene glycol with a molecular weight of 3000 and0.1 g of zinc acetate, to obtain 315 g of a polyester copolymer. Thepolyoxyethylene chain content of the obtained polyester copolymer wasapproximately 26 mass %, and the 200° C. melt viscosity was 10,000mPa·s.

EXAMPLE 7

The same procedure was carried out as in Example 1, except for charginginto the reactor 129.6 g (0.6 mol) of 1,8-naphthalenedicarboxylic acid,118.4 g (0.4 mol) of dimethyl 5-sulfoisophthalate sodium salt, 57 g ofethylene glycol, 85 g of polyethylene glycol with a molecular weight of1000 and 0.1 g of zinc acetate, to obtain 343 g of a polyestercopolymer. The polyoxyethylene chain content of the obtained polyestercopolymer was approximately 24 mass %, and the 200° C. melt viscositywas 11,000 mPa·s.

EXAMPLE 8

The same procedure was carried out as in Example 1, except for charginginto the reactor 58.8 g (0.6 mol) of maleic anhydride, 118.4 g (0.4 mol)of dimethyl 5-sulfoisophthalate sodium salt, 58 g of ethylene glycol, 68g of polyethylene glycol with a molecular weight of 1000 and 0.1 g ofzinc acetate, to obtain 267 g of a polyester copolymer. Thepolyoxyethylene chain content of the obtained polyester copolymer wasapproximately 25 mass %, and the 200° C. melt viscosity was 10,000mPa·s.

EXAMPLE 9

The same procedure was carried out as in Example 1, except for charginginto the reactor 116.4 g (0.6 mol) of dimethyl terephthalate, 118.4 g(0.4 mol) of dimethyl 5-sulfoisophthalate sodium salt, 83 g of1,4-butanediol, 83 g of polyethylene glycol with a molecular weight of1000 and 0.1 g of zinc acetate, to obtain 337 g of a polyestercopolymer. The polyoxyethylene chain content of the obtained polyestercopolymer was approximately 24 mass %, and the 200° C. melt viscositywas 11,000 mPa·s.

EXAMPLE 10

The same procedure was carried out as in Example 1, except for charginginto the reactor 116.4 g (0.6 mol) of dimethyl terephthalate, 118.4 g(0.4 mol) of dimethyl 5-sulfoisophthalate sodium salt, 96 g of neopentylglycol, 83 g of polyethylene glycol with a molecular weight of 1000 and0.1 g of zinc acetate, to obtain 350 g of a polyester copolymer. Thepolyoxyethylene chain content of the obtained polyester copolymer wasapproximately 23 mass %, and the 200° C. melt viscosity was 12,000mPa·s.

EXAMPLE 11

The same procedure was carried out as in Example 1, except for charginginto the reactor 116.4 g (0.6 mol) of dimethyl terephthalate, 118.4 g(0.4 mol) of dimethyl 5-sulfoisophthalate sodium salt, 310 g of abisphenol S-ethylene oxide 2 mol adduct, 83 g of polyethylene glycolwith a molecular weight of 1000 and 10.1 g of zinc acetate, to obtain564 g of a polyester copolymer. The polyoxyethylene chain content of theobtained polyester copolymer was approximately 14 mass %, and the 200°C. melt viscosity was 12,000 mPa·s.

EXAMPLE 12

The same procedure was carried out as in Example 1, except for charginginto the reactor 116.4 g (0.6 mol) of dimethyl terephthalate, 124.8 g(0.4 mol) of dimethyl 5-sulfoisophthalate potassium salt, 57 g ofethylene glycol, 86 g of polyethylene glycol with a molecular weight of1000 and 0.1 g of zinc acetate, to obtain 320 g of a polyestercopolymer. The polyoxyethylene chain content of the obtained polyestercopolymer was approximately 26 mass %, and the 200° C. melt viscositywas 14,000 mPa·s.

EXAMPLE 13

The same procedure was carried out as in Example 1, except for charginginto the reactor 116.4 g (0.6 mol) of dimethyl terephthalate, 118.4 g(0.4 mol) of dimethyl sulfoterephthalate sodium salt, 57 g of ethyleneglycol, 86 g of polyethylene glycol with a molecular weight of 1000 and0.1 g of zinc acetate, to obtain 314 g of a polyester copolymer. Thepolyoxyethylene chain content of the obtained polyester copolymer wasapproximately 27 mass %, and the 200° C. melt viscosity was 15,000mPa·s.

EXAMPLE 14

The same procedure was carried out as in Example 1, except for charginginto the reactor 116.4 g (0.6 mol) of dimethyl terephthalate, 124.8 g(0.4 mol) of dimethyl sulfoterephthalate potassium salt, 57 g ofethylene glycol, 86 g of polyethylene glycol with a molecular weight of1000 and 0.1 g of zinc acetate, to obtain 320 g of a polyestercopolymer. The polyoxyethylene chain content of the obtained polyestercopolymer was approximately 26 mass %, and the 200° C. melt viscositywas 13,000 mPa·s.

EXAMPLE 15

The same procedure was carried out as in Example 1, except for charginginto the reactor 116.4 g (0.6 mol) of dimethyl terephthalate, 129.6 g(0.4 mol) of diethyl 4-sulfophthalate sodium salt, 57 g of ethyleneglycol, 86 g of polyethylene glycol with a molecular weight of 1000 and0.1 g of zinc acetate, to obtain 297 g of a polyester copolymer. Thepolyoxyethylene chain content of the obtained polyester copolymer wasapproximately 28 mass %, and the 200° C. melt viscosity was 12,000mPa·s.

EXAMPLE 16

The same procedure was carried out as in Example 1, except for charginginto the reactor 116.4 g (0.6 mol) of dimethyl terephthalate, 136.0 g(0.4 mol) of diethyl 4-sulfophthalate potassium salt, 57 g of ethyleneglycol, 86 g of polyethylene glycol with a molecular weight of 1000 and0.1 g of zinc acetate, to obtain 303 g of a polyester copolymer. Thepolyoxyethylene chain content of the obtained polyester copolymer wasapproximately 27 mass %, and the 200° C. melt viscosity was 12,000mPa·s.

COMPARATIVE EXAMPLE 1

The same procedure was carried out as in Example 1, except for charginginto the reactor 174.6 g (0.9 mol) of dimethyl terephthalate, 29.6 g(0.1 mol) of dimethyl 5-sulfoisophthalate sodium salt, 58 g of ethyleneglycol, 74 g of polyethylene glycol with a molecular weight of 1000 and0.1 g of zinc acetate, to obtain 272 g of a polyester copolymer. Thepolyoxyethylene chain content of the obtained polyester copolymer wasapproximately 26 mass %, and the 200° C. melt viscosity was 9200 mPa·s.

COMPARATIVE EXAMPLE 2

In a reactor there were charged 58.2 g (0.3 mol) of dimethylterephthalate, 207.2 g (0.7 mol) of dimethyl 5-sulfoisophthalate sodiumsalt, 60 g of ethylene glycol, 90 g of polyethylene glycol with amolecular weight of 2000 and 0.1 g of zinc acetate, and the temperaturewas increased from 150° C. to 230° C. over a period of 3 hours withstirring under a nitrogen gas atmosphere for transesterification, whiledistilling out the methanol from the system. Next, 0.1 g of tetrabutyltitanate was added and the pressure was gradually reduced, but stirringbecame impossible when the internal pressure reached approximately 30kPa, and the reaction could not be continued.

COMPARATIVE EXAMPLE 3

The same procedure was carried out as in Example 1, except for charginginto the reactor 116.4 g (0.6 mol) of dimethyl terephthalate, 118.4 g(0.4 mol) of dimethyl 5-sulfoisophthalate sodium salt, 56 g of ethyleneglycol, 83 g of polyethylene glycol with a molecular weight of 800 and0.1 g of zinc acetate, to obtain 310 g of a polyester copolymer. Thepolyoxyethylene chain content of the obtained polyester copolymer wasapproximately 26 mass %, and the 200° C. melt viscosity was 9700 mPa·s.

COMPARATIVE EXAMPLE 4

The same procedure was carried out as in Example 1, except for charginginto the reactor 116.4 g (0.6 mol) of dimethyl terephthalate, 118.4 g(0.4 mol) of dimethyl 5-sulfoisophthalate sodium salt, 61 g of ethyleneglycol, 83 g of polyethylene glycol with a molecular weight of 4000 and0.1 g of zinc acetate, to obtain 315 g of a polyester copolymer. Thepolyoxyethylene chain content of the obtained polyester copolymer wasapproximately 26 mass %, and the 200° C. melt viscosity was 10,000mPa·s.

COMPARATIVE EXAMPLE 5

In a reactor there were charged 116.4 g (0.6 mol) of dimethylterephthalate, 118.4 g (0.4 mol) of dimethyl 5-sulfoisophthalate sodiumsalt, 62 g of ethylene glycol, 24 g of polyethylene glycol with amolecular weight of 2000 and 0.1 g of zinc acetate, and the temperaturewas increased from 150° C. to 230° C. over a period of 3 hours withstirring under a nitrogen gas atmosphere for transesterification, whiledistilling out the methanol from the system. Next, 0.1 g of tetrabutyltitanate was added and the pressure was gradually reduced, but stirringbecame impossible when the internal pressure reached approximately 40kPa, and the reaction could not be continued.

COMPARATIVE EXAMPLE 6

The same procedure was carried out as in Example 1, except for charginginto the reactor 116.4 g (0.6 mol) of dimethyl terephthalate, 118.4 g(0.4 mol) of dimethyl 5-sulfoisophthalate sodium salt, 49 g of ethyleneglycol, 218 g of polyethylene glycol with a molecular weight of 1000 and0.1 g of zinc acetate, to obtain 438 g of a polyester copolymer. Thepolyoxyethylene chain content of the obtained polyester copolymer wasapproximately 48 mass %, and the 200° C. melt viscosity was 11,000mPa·s.

COMPARATIVE EXAMPLE 7

In a reactor there were charged 116.4 g (0.6 mol) of dimethylterephthalate, 118.4 g (0.4 mol) of dimethyl 5-sulfoisophthalate sodiumsalt, 57 g of ethylene glycol, 83 g of polyethylene glycol with amolecular weight of 1000 and 0.1 g of zinc acetate, and the temperaturewas increased from 150° C. to 230° C. over a period of 3 hours withstirring under a nitrogen gas atmosphere for transesterification, whiledistilling out the methanol from the system. Next, 0.1 g of tetrabutyltitanate was added and the pressure was gradually reduced, and when theinternal pressure reached approximately 30 kPa, reaction was terminatedand the mixture was cooled to obtain 312 g of a polyester copolymer. Thepolyoxyethylene chain content of the obtained polyester copolymer wasapproximately 26 mass %, and the 200° C. melt viscosity was 3200 mPa·s.

COMPARATIVE EXAMPLE 8

In a reactor there were charged 116.4 g (0.6 mol) of dimethylterephthalate, 118.4 g (0.4 mol) of dimethyl 5-sulfoisophthalate sodiumsalt, 57 g of ethylene glycol, 83 g of polyethylene glycol with amolecular weight of 1000 and 0.1 g of zinc acetate, and the temperaturewas increased from 150° C. to 230° C. over a period of 3 hours withstirring under a nitrogen gas atmosphere for transesterification, whiledistilling out the methanol from the system. Next, 0.1 g of tetrabutyltitanate was added and the pressure was gradually reduced to an internalpressure of approximately 9 kPa, and reaction was conducted at 250° C.for 5 hours to obtain 311 g of a polyester copolymer. Thepolyoxyethylene chain content of the obtained polyester copolymer wasapproximately 26 mass %, and the 200° C. melt viscosity was 25,000mPa·s.

The results from synthesizing these polyester copolymers are summarizedin Table 1.

TABLE 1 Sulfonate group/ total dibasic acid Polyoxyethylene 200° C.components chain content Melt viscosity (mol %) (mass %) (mPa · s)Example 1 40 27 12000 Example 2 20 38 20000 Example 3 30 38 8100 Example4 50 13 8900 Example 5 60 13 7500 Example 6 40 26 10000 Example 7 40 2411000 Example 8 40 25 10000 Example 9 40 24 11000 Example 10 40 23 12000Example 11 40 14 12000 Example 12 40 26 14000 Example 13 40 27 15000Example 14 40 26 13000 Example 15 40 28 12000 Example 16 40 27 12000Comp. Ex. 1 10 26 9200 Comp. Ex. 2 70 25 reaction not continued Comp.Ex. 3 40 26 9700 Comp. Ex. 4 40 26 10000 Comp. Ex. 5 40 9 reaction notcontinued Comp. Ex. 6 40 48 11000 Comp. Ex. 7 40 26 3200 Comp. Ex. 8 4026 25000

The oligomer removing agents obtained in the examples and comparativeexamples were evaluated in the following manner.

Oligomer Removing Power Test

For comparison of the oligomer removing effects during dyeing, polyestersatin woven fabrics containing the oligomer removing agents of Examples1-16 and Comparative Examples 1, 3, 4 6-8 and dyed under the followingconditions were subjected to extraction using 1,4-dioxane, and the UVabsorbance of the extracts at 286 nm were measured to calculated theoligomer deposition per gram of fabric.

The results are shown in Table 2.

Dyeing bath Dye: C.I. Disperse Blue 79 1% o.w.f. 80% Acetic acid 1 g/LDisperse level dyeing agent: NICCA SANSOLT 1 g/L SN-558 (Nicca ChemicalCo., Ltd.) Oligomer removing agent 0.3 g/L   Dyeing temperature × time:130° C. × 30 minutes Liquor to goods ratio = 15:1

Dye Dispersibility Test

For comparison of the dye dispersibilities during dyeing, a scouredpolyester knit was wrapped around the holder of a CARAPET (NihonSenshoku Kikai Co.) and anchored above and below with rubber bands, andthis was dyed under the conditions described below with addition of oneof the oligomer removing agents of Examples 1-16 or Comparative Examples1, 3, 4 and 6-8, after which the extent of casing spots left on thepolyester knit was visually observed and the dye dispersibility wasevaluated on a 5-level scale, from 5 (no casing spots) to 1 (numerouscasing spots).

The results are shown in Table 2.

Dyeing bath Dye: C.I. Disperse Red 167 2% o.w.f. 80% Acetic acid 1 g/LDisperse level dyeing agent: NICCA SANSOLT 1 g/L SN-558 (Nicca ChemicalCo., Ltd.) Oligomer removing agent 0.3 g/L   Dyeing temperature × time:115° C. × 1 minute Liquor to goods ratio = 30:1

Persistence Test

For comparison of the persistences of the oligomer removing agents ontodyed fabrics, polyester satin woven fabrics dyed under the same dyeingconditions as in the oligomer removing power test described above weredried at 120° C. for 1 minute and then heat treated at 180° C. for 30seconds. After then cooling to room temperature, a single drop of waterwas dropped onto the fabric and the time until complete permeation ofthe water drop from the fabric surface was measured. A lack of waterabsorption is judged as a lack of persistence of the oligomer removingagent.

The results are shown in Table 2.

Processing Suitability Test

For comparison of the processing suitability for dyeing, ahigh-temperature, high-pressure jet dyeing machine (MINI-JET D-100 byTexam Co., Ltd.) was used for placement of a polyester pongee in atreatment bath containing the oligomer removing agent of one of Examples1-16 or Comparative Examples 1, 3, 4 and 6-8 under the conditionsdescribed below, and the condition of bubbles between 60-130° C. with aheating rate of 3° C./min was compared to one without addition of anoligomer removing agent. The evaluation was conducted on a 3-level scaleof A (equivalent to no addition), B (more foaming than with no addition)and C (considerable foaming compared to no addition), and samples withminimal foaming were judged as satisfactory.

The results of the evaluation are shown in Table 2.

Treatment bath 80% Acetic acid 1 g/L Disperse level dyeing agent: NICCASANSOLT 1 g/L SN-558 (Nicca Chemical Co., Ltd.) Oligomer removing agent0.3 g/L   Liquor to goods ratio = 30:1

TABLE 2 Oligomer Oligomer removal deposition Dye Persistence Processingagent mg/g dispersibility (sec) suitability Example 1 9.7 5 180< AExample 2 10.4 5 180< A Example 3 10.1 5 180< A Example 4 11.7 5 180< AExample 5 11.3 5 180< A Example 6 18.8 5 180< A Example 7 10.3 5 180< AExample 8 11.9 5 180< A Example 9 11.1 5 180< A Example 10 10.8 5 180< AExample 11 10.9 5 180< A Example 12 10.1 5 180< A Example 13 9.9 5 180<A Example 14 10.3 5 180< A Example 15 10.7 5 180< A Example 16 10.9 5180< A Comp. Ex. 1 25.8 5 180< A Comp. Ex. 3 26.7 5 180< A Comp. Ex. 418.8 2 180< B Comp. Ex. 6 26.5 2 180< C Comp. Ex. 7 28.4 5 180< A Comp.Ex. 8 9.3 5 30 A None used 29.0 5 180< A

As seen by the results in Table 2, the oligomer removing agents of theinvention examples were able to reduce the amount of oligomers withoutaffecting the dyeing property, and also exhibited good processingsuitability evidenced by low foaming during processing.

INDUSTRIAL APPLICABILITY

Using an oligomer removing agent according to the invention can yieldfiber products with satisfactory quality and no processing defectsarising from oligomer deposition, while permitting more economicaldyeing of fiber products due to reduced foaming during processing andthus less frequent occurrence of trouble during processing.

1. An oligomer removing agent for polyester-based fiber materials,comprising a polyester copolymer which is obtained by polycondensationof a dibasic acid component containing 15-65 mol % of a sulfonategroup-containing dibasic acid and a dihydric alcohol componentcontaining polyethylene glycol with a molecular weight of 900-3500, andwhich has a 200° C. melt viscosity of 5000-23,000 mPa·s and has 10-40mass % polyoxyethylene chain in the molecule.